The 10.9.1 update improves the stability and compatibility of your Mac.

This update includes the following fixes:• Improved support for Gmail in OS X Mail, and fixes for users with custom Gmail settings• Improves the reliability of Smart Mailboxes and search in Mail• Fixes an issue that prevented contact groups from working properly in Mail• Resolves an issue that prevented VoiceOver from speaking sentences that contain emoji• Updates Shared Links periodically when open in the Safari Sidebar